From: H Hartley Sweeten Date: Mon, 5 Oct 2015 22:33:14 +0000 (-0700) Subject: staging: comedi: multiq3: document the encoder chip commands X-Git-Tag: firefly_0821_release~176^2~802^2~907 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=014d8414ce40e3f2e9733bdde39f474299283290;p=firefly-linux-kernel-4.4.55.git staging: comedi: multiq3: document the encoder chip commands Add some comments to document the commands that are sent to the encoder chips. Signed-off-by: H Hartley Sweeten Signed-off-by: Ian Abbott Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/staging/comedi/drivers/multiq3.c b/drivers/staging/comedi/drivers/multiq3.c index dac1879fc86f..02d41fc4d82f 100644 --- a/drivers/staging/comedi/drivers/multiq3.c +++ b/drivers/staging/comedi/drivers/multiq3.c @@ -65,17 +65,17 @@ #define MULTIQ3_ENC_CTRL_REG 0x0e /* - * flags for encoder control + * Encoder chip commands (from the programming manual) */ -#define MULTIQ3_CLOCK_DATA 0x00 -#define MULTIQ3_CLOCK_SETUP 0x18 -#define MULTIQ3_INPUT_SETUP 0x41 -#define MULTIQ3_QUAD_X4 0x38 -#define MULTIQ3_BP_RESET 0x01 -#define MULTIQ3_CNTR_RESET 0x02 -#define MULTIQ3_TRSFRPR_CTR 0x08 -#define MULTIQ3_TRSFRCNTR_OL 0x10 -#define MULTIQ3_EFLAG_RESET 0x06 +#define MULTIQ3_CLOCK_DATA 0x00 /* FCK frequency divider */ +#define MULTIQ3_CLOCK_SETUP 0x18 /* xfer PR0 to PSC */ +#define MULTIQ3_INPUT_SETUP 0x41 /* enable inputs A and B */ +#define MULTIQ3_QUAD_X4 0x38 /* quadrature */ +#define MULTIQ3_BP_RESET 0x01 /* reset byte pointer */ +#define MULTIQ3_CNTR_RESET 0x02 /* reset counter */ +#define MULTIQ3_TRSFRPR_CTR 0x08 /* xfre preset reg to counter */ +#define MULTIQ3_TRSFRCNTR_OL 0x10 /* xfer CNTR to OL (x and y) */ +#define MULTIQ3_EFLAG_RESET 0x06 /* reset E bit of flag reg */ #define MULTIQ3_TIMEOUT 30